Acoustic apparatus, particularly signaling apparatus



March 25, 1930. H. KUCHENMEISTER 1,752,185

ACOUSTIC APPARATUS, PARTICULARLY SIGNALING APPARATUS Filed Oct. 4. 1926 d /t. HEN/V 572-5 I Patented Mar. 25, 1930 UETED STATE HEINRICH KtioHENMErsTER, or BER-LIN, GERMANY Application filed October 4, 1926, Serial No.

It is already known that the volume of a sound can be amplified and its carrying capacity multiplied by artificially setting up a phase displacement and by suitably selecting the resulting interval in a definite suc cession of sounds.

The present invention makes use of this known fact in order to set up, for example in the case of acoustic signals that are to-be 1::- clearly audible ata distance, those conditions which, by generating the sound repeatedly at predetermined intervals, impart the so-called carrying'volume to the resulting sound. 7

Acoustic signals of this kind are required,

for example, in the case of sirens, doublebell signals, fire-alarm signals, factory time signals, foghorns, danger signals on the high seas, &c. For use at seat, in particular, the problem is not to disturb or even alarm the unconcerned coastal population or the passengers aboard ship by a sig'nalin the form of a shrill, loud note, discord or dissonance, but to produce a signal which, without being disturbing, has a wide effective range corre-.

sponding to the special circumstances, and the intensity of which can be controlled from a receiving station far removed from the sending station. Contrary to. previous thought, the problem cannot be solved by gencrating a very powerful note for emission, by means of externally supplied extraneous en-. ergy; but it can be solved-by imparting'to the note or notes, at the time of production at the sending station, those specific properties which enable them to act on the organs of hearing at remote receiving "stations, by reason of their ample volume, both by means of longitudinal waves and also, in suitable places, by means of transverse waves.

According to the invention, this result is achieved by repeatedly exciting the signaling instrument or 'apparatus'in question by separate impulses that succeed each other at in tervals of less than one third of asecond. -By way of example, several acoustic sig- 139,547, and in Germany Octojoer 28, 1925.

naling generators suitable for carrying the invention into practice are illustrated in the accompanying drawing.

Figs. 1 and 2 show, in section and front elevation respectively, a siren operated by compressed air; Fig. 3 is a steam whistle, with double pipe; and Figs. 4, 5 and 6 show a double-bell signaling device in side elevation, part front elevation and perspective View respectively.

lVith reference to Fig. 1, it should be stated that the intention is to operate in known manner, through the compressed air pipe at, a siren consisting of a perforated rotating disc Z) and a fixed perforated disc 0, both of which are enclosed in a casing d. The holes in the rotary disc .7) are marked f, and those in the fixed disc 0 are marked a. Thenumber of holes 6: f, the number of revolutions of the disc Z), and the'air pressure are selected'so I that-taking the rotational velocity into considerationidentical sound impulses are generated at intervals of about th to (for example) 1/80th of a second." In this'way a full note is produced,'the rangejof whichwill be the greater in proportion as the selected interval increases. The explanation of the effect is that, under certain conditions'ascertained'by experiment and afterwards se-T lectively adjustablean assimilation and acing efiect on the human-ear.

The limit in the selection of the interval is the distance at which the sounds no longer superimpose even further away. According to the invention, a plurality of successively produced sounds+equal energy of excitation 8 being premised carry very much further than a sound generated continuously by the usual sirens which,1as is known,run at very high speeds; and this is quite apart from the consideration that the character of such a sound is unnecessarily disturbing, disagreeable and shrill.

A signal generator in the form of steam whistles (Fig. 3) can be employed in the same way. The steam whistles themselves are denoted by and 70 the casing by i; and the control valve, or similarregulating device, by g In the manner already described, the steam whistles are excited in repeated succession and at predetermined intervals under the control of the valve 9 which has ports 7L and revolves at a determined speed. The steam unay be replaced by compressed air, thus giving a pneumatic whistle.

The desired effect. can be obtained by mounting the two steam whistles 7c and 76 side by side as shown and making the impulse for the second note commence before the note first produced has completely subsided. This can be done by arrangingthe spacing of the ports h and suitably adjusting the number of revolutions of the valve 5 In Fig. 3, the whistles are both of approximately equal size,

because they are intended to produce only a slight difference in tone for sound oscillations. If the signal is to be of the double-note type,'the whistles k and 70 must difier substantially from each other in respect of length and other particulars. 7

Figs. 4, 5 and 6 represent the application of the invention to a double-bell signaling device in which the bells are tuned to difierent notes, for example A and G-sharp. ZzZ denote two shafts each provided with adjustable cams m m having a definite offset, said cams acting in knownimanner on thehammers n of bells 0. The shafts Z zZ are connected together, and uniform speed is obtained, by

" means of a connection p, which may be of the belt, chain, rope or cord type. To allow for slip, the. pulley ofthe driven shaftmay be of slightly larger diameter than the pulley of the driving shaft.

The effect of this double-bell signaling de vice is intensifiedby repeatedly exciting two (or more) bells having the same fundamental note at an optimum interval which must first be ascertained by .experiment. In

interval, a sound of different pitch is superimposed in the same manner, thus produclng an agreeable resultant note of wide range.

Having now fully described my invention,

parallel therewith, or also offset by the selected what I claim and desire to secure by Letters Patent is 1 V 1. A method of audible signaling consisting in repeatedly exciting a sound generator by individual sound impulses that succeed one another at intervals of less than one third of a second. V

2. Acoustic apparatus comprising a sound generator and means whereby the sounds to be emitted from said generator can be excited by individual impulses that succeed one another at intervals of less than one third 7 of a second.

3. Acoustic apparatus comprising a sound generator, means whereby sounds can be excited from said generator, and means for controlling said eXcitation to ensure individual sound impulses that'suc'ceed one another at intervals of less than one third of a second.

4. Acoustieapparatus comprising a plu rality of sound emitters, means for repeatedly exciting sald emitters with a phase displacement to ensure that an impulse for one emitter begins before an impulse for another emitter has ceased, andmeans whereby the individual sound impulses from each emltter another at intervals of less than one third of a second. V

6. Acoustic slgnaling apparatus comprising a hollow casing for the admission of pressure fluid, means associated with the casing upon whichsaid fluid acts to generate sound waves, and means for repeatedly interrupting the action of said fluid to give sound impulses that succeedv one another at less than one third of a second. 7. Acoustic signalingapparatus comprising a hollow casing for the admission of pressure fiuid, means associated with the casing uponwhich said fluid acts to enerate sound waves, and a perforated member movable in the casing for repeatedly'interrupting theaction of said fluid to give sound impulsesthat succeed one another at-less than on'ethird of a second. p 8. Acoustic signaling apparatus comprising a hollow casing having inlet andoutlet openings for the passage therethrough of pressure fluid, and a member rotatable in the casing past said outlet openings'to produce by said pressure fluid sound impulses that succeed one another at an interval of less than one third of a second. p

. 9. Acoustic signaling apparatus compris ing a hollow casing having an inlet for-pressure fluid, whistle pipes in communication with the casing, and a member rotatable in the casing past the inlets to said pipes in order to produce by said pressure fluid sound impulses that succeed one another at an interval of less than one third of a second.

10. Acoustic apparatus comprising a sound generator, means for successively exciting the sounds to be emitted from said generator by individual impulses that succeed one another at intervals of less than one third of a second, and means whereby said time interval can be adjusted.

11. Acoustic apparatus comprising a sound generator, means whereby sounds can be excited from said generator, and means for variably controlling said excitation to ensure individual sound impulses that succeed one another at intervals of less than one third of a second. v

12. Acoustic apparatus comprising a plurality of sound generators, means for repeatedly exciting said generators with a phase displacement to ensure that an impulse for one generator begins before an impulse for another generator has ceased, means whereby the individual sound impulses emitted from each generator can be made to succeed one another at intervals of less than one third of a second, and means whereby said time interval can be adjusted. v

13. Acoustic apparatus comprising a plurality of sound generators of difi'erent pitch, means for repeatedly exciting said generators with a phase displacement to ensure that an impulse for one generator begins before an impulse for another generator has ceased, means whereby the individual sound impulses emitted from each generator can be made to succeed one another at intervals of less than one third of a second, and means whereby said time intervals can be. adjusted.

1%. Acoustic signaling apparatus compris ing a hollow casingfor the admission of 1 pressure fluid, means associated with thecasing upon whlch said fluld acts to generate sound waves, mean sfor repeatedly interrupting the action of said fluid to give sound impulses that succeed one another at less than one third of a second, and means whereby the time interval can be adjusted.

15. Acoustic signaling apparatus, comprising a hollow casing for the admissionof pressure fluid, means associated with the casing upon which said fluid acts to generate sound Waves, a perforated member movable in the casing for repeatedly interrupting the action of said fluid to give sound impulses that succeed one another at less than one third of a second, and means whereby the time interval by individual impulses that succeed one another at intervals of less than one third of a second.

17. Acoustic apparatus comprising a plurality of sound generators, and means for ex citing in variable relation sounds of difi'erent HEINRICH KI'JGHENMEISTER. 

